Don't be curmudgeonly. Thoughtful criticism is fine, but please don't be rigidly or generically negative.
I think though, "write-only" third-party contributions are a necessary evolutionary step towards a more balanced ecosystem, so lack of an open reference could lead to the needed experimentation, both legal and technical
Apple doesn't support Asahi specifically but did build in the capability to boot another OS and intentionally does not block it.
One is cracking open a door (Apple) and the other is opening the door wide, and welcoming you into your home.
Didn't mean to imply that Aapl can't be accused of perfidious behaviour on the sw side, but the erstwhile welcomes mean that Goog's betrayal, when it happens, even a minor one that doesn't kill the biz, hurts a lot more?
To play devil's advocate though, Darwin is technically open source?
Removing support for Pixel devices makes AOSP even less useful for developers, because belief that VM will be a good replacement for real hardware test environment is a fairy tale next to sleeping beauty.
So no, they don't provide "entire operating system source code", what they provide is a caricature of open source project. So maybe they should call it COSP.